Etching process



Sept. 5, 1950 E. B. oT'r 2,521,648

ETcHING PRocEss Filed Jan. 29, 1945 2 sheets-sheet 1 @wam Sept. 5, 1950 E. B. OTT 2,521,648

ETCHING PRocr-:ss

Filed Jan. 29, 1945 2 sheets-sheet 2.

7 C y d y jf, I I' 76H50 IN V EN TOR. 4PM/5.97 07-7- mfg.

Patented Sept. 5, 1950 Ernest B. Ott, Chicago, Ill., assignor `to. Croname,

Incorporated, Chicago, Ill., la corporation ofv Illinois y ApplicatiaJanua'ry 29,1945, salama-575,161 f comme. (01.41-43) V l The invention herein disclosed relates to decv orating processes involving vetched finishes.

eneral objects of the invention areto simplifyy and reduce the number of steps .and apparatus required and to accomplish savingsintirne and expense, as compared with previous etching methods.

Further objects are to produce a better product, both in appearance and in physical characteristics, such as in matters of greater durability, wear and weather resisting qualities.

Other objects are to make possible many `dif ferent variations in the decoration of articles, such as in matters of applying decoration to previously shaped or formed articles, or to one or both sides of a sheet and, in the klatter event, to accomplish this with only a single etching step and with the same exact register for both sides.-

Other desirable objects and the novel features by which the purposes of the invention are attained are set forth or will appear inthe course final results accomplished by the invention, butI with the thought-that various changes and modification as to this illustration may be made Without departure from the true spirit and broad scope of the invention as hereinafter defined and claimed.

Fig. l in the drawing is a perspective and part sectionalview illustrating therst step of printing or applying the material which is to form the final decorative enamel; v

Fig. 2 is a similar view illustrating the step of baking to convert the appliedv coating material to a hard, acid resistant enamel;

Fig. 3 is a like view illustratingthe third `and nal step of etching the uncovered surface not protected by the enamel;

Fig. 4 is a view like the preceding but illus-` trating a reverse effect with raised background and sunken characters;

Fig. 5 is a part sectional perspective view illustrating the sheet of Fig. 2, printed and baked on one side, as having been printed on the opposite side;

Fig. 6 is a similar view, after baking on the second side; and

Fig. '7 is a like view of the sheet after a single etching of both sides.

Briefly stated, the invention resides in applying the desired design, either in raised or sunken characters, with an enamel which will bake to a hard, acid resistant condition, then baking to convert the covered or what may be termedthey printed portions to` ahard ornamentalvres'ist which will constitutevthe final applieddecora-I tion, and then etching the unprinted, uncovered? portions. f Y Y .In Fig. 1 a plate is indicated at T having far desired design printed thereon in enamel -at 8.` f

Fig.V 2Y illustrates in exaggeratedformfiiw thei enamel may appear after baking into the form of'V a hard, permanent, acid resistant coating.

`With the baked enamel thenforming--an acid resist as Well as a permanent and final decorativel coating, the article may be subjected to any usual or special etching process to etch the unprinted," uncovered surface portions, indicated at-f9gFigl B' If sunken characters are to be producedfthe: background surface portions may be coated and; baked as indicated at vila. in Fig. 4, and the char# acter forming portions be left runcovered antigri-Vl terwards etched as shown at 9a. The characters, outlines or designs, veither raised or sunken as illustrated, may be produced in any one or any numberof colors,- the inven'; tion thus affording the opportunity for--usefof multi-colors, color l:Filling and varied backgrounds,` borders and designs. 'f *l f The same processing may be applied to ,both sides of thesheet and with important attendant advantages. f

Fig. 5 shows how after printing land baking-atr 8, on one side, the sheetr maybe printed at I lll on the opposite side, with similarenamel, eitherf in the same or different outline and in the same" or different color. vAs upto this timel the sheet, has'not'been etched, "the edge of the she'et'us'ed for register remains unimpaired and so can'v vbef used for accurately registering the designio he second side.

-The design on the second side is then baked' hard, as indicated in Fig. 6.

With both sides printed and baked, the sheet may be put in the etching solution and both sides etched at once, as indicated at Il, Fig. 7.

This single etching step reduces costs to the point of making practical the decorating of both sides in instances which would have been prohibitive from the cost standpoint under old methods.

Instead of printing a design on the second side or back, all or a portion of the back may be coated With a color enamel, for decorative purposes, this being baked to act as a resist in the subsequent etching step. ri`his is particularly desirable for decoratively finishing the backs or irregular or variously formed shapes. This dec,

the etching second, or third and fourth colors may be applied Thus after right over the first and baked, to build up Amulti.-

color designs, followed by etchingof the surfaces left uncovered. Similarly, double or multiple etching may :be practiced to bringeoutthe ,grain of the material and for other decorative effects. The invention is applicable to all the common metals, such as aluminum, zinc, nickel-silver,

coppa', orfcopper alloys, Monel metals, stainless.

steelyand-,toother materials tha-n metals, such as plasticsand substances which can be acted on by acidsfor alkalines in solutions.

'Ihe article to which the process is appliedmay be plain or mayhave'beenpreviously treated or prepared-as by plating, coating, forming, bending; embossing, spinning, piercing',- machining, weldingv or-other processing. Any such treatment, preparation of surface or preparation by way ofshapingmay precede the present decorating-and etching process here disclosed.

Multipledesigns may be produced by applying the-stepsnf.thisinvention to-'a lpiece having all or parts of its surface previously etched or possibly-both etched and colored. Thus, for example, thepresent invention may be applied to a plate havingpart of` the background colored black with an. etched hidden metal design under the black.

While usually they hard, resist, enamel forming color maybe applied by ordinary printingand screening methods, the invention contemplates that this colormay be applied in any Way, as by hand, by decalcomania or otherwise.

For general purposes an enamel has been used such as disclosed in the three examples given in Patent 2,279,496 issued April 14, 1942, comprising an .alkyd resin base colored with organic pigment and properly reduced to a correct viscosity for printing, screening, stenciling or other method suited tothe application to the object to be decorated. Other materials possessing similar resistantproperties and of suitable viscosity may be,used,.particular attention being exercised that the vsolvents, employed .are suitable for the base materials treated, such as certain types of rplastic or fibre.

The method disclosed gives a deeper, sharper:

outline to the characters and promotes readr :fragility of the decorated surfaces.

ability and rpermanency of character because of the extreme relief or difference in elevation of the contrasted surfaces.

The hard, baked enamel forming the surface of the highlights has better wearing qualities and is less liable to damage than the ordinary coats of decorative enamel applied on plates etched in the; ordinary manner. The,l color` permanence is better v'and the productstande upfbetter under weather exposure.

The invention makes possible a high degree of accuracy in design. Greater handling facility is achieved because of shorter intervals of preparationand fewer production steps and reduced The product, while of a higher-or better quality, actually is of less cost. Many designs impossible of attainment under normal iithographic production methods,

' such as unusual and odd shapes, may be produced with this invention, particularly by screening or screen printing andv use of decalcomanias preparedcwith the etchant resistant nal colors such as described;

claimedxis:

' f1- The: herein disclosed method of producing. etched articles which comprises applyingA designsy in permanent enamel forming resist to the oppositefsides-of a plate, employing the same original edgefof-:they plate for register of the designs on both sides,.treating,to convert the enamel to hard, permanent enamel resist'on vboth sides of the plate and theny simultaneously etching both sides offtheplate in :if-single etching operation.

2. The herein` disclosed method of producing an etched article which comprises printing directly-'on the surface of an article the design whichy isi'toV constitute the highlight with an alkyd resinpaste.: which will bake to a hard, permanent, acidpresistant nish forming enamel, baking to tra-nsfoirrithey printed. material to the permanent fnishedhighlight and which in such state without further treatmentjwill constitute a resist for etolu'ngpurposes, and" thenetching those portions of the surface left exposed .by said printed resist and nal finish forming enamel.

ERNEST B. OTT,

REFERENCES CITED The-following. references are of record in the 

1. THE HEREIN DISCLOSED METHOD OF PRODUCING ETCHED ARTICLES WHICH COMPRISES APPLYING DESIGNS IN PERMANENT ENAMEL FORMING RESIST TO THE OPPOSITE SIDES OF A PLATE, EMPLOYING THE SAME ORIGINAL EDGE OF THE PLATE FOR REGISTER OF THE DESIGNS ON BOTH SIDES, TREATING TO CONVERT THE ENAMEL TO HARD, PERMANENT ENAMEL RESIST ON BOTH SIDES OF THE PLATE AND THEN SIMULTANEOUSLY ETCHING BOTH SIDES OF THE PLATE IN A SINGLE ETCHING OPERATION. 